Protecting and cleaning means for movable electrical contact elements



Jun 12. 1956 E. H. GUBOFF PROTECTING AND CLEANING MEANS FOR MOVABLE ELECTRICAL CONTACT ELEMENTS Filed Nov. 10, 1952 IN V EN TOR.

United States Paten PROTECTING AND CLEANING MEANS FOR MOV- ABLE ELECTRICAL CONTACT ELEMENTS Edward H. Gubotf, Los Angeles, Calif., assignor to Chi cago City Bank and Trust Company, a corporat on Application November 10, 1952, Serial No. 319,703

4 Claims. (Cl. 200-166) This invention relates to protecting and cleaning means for movable electrical contact elements, such as the drum supported contact elements in television tuning units, and other places, where groups of movable contact elements are moved as a unit into contact with corresponding fixed contact elements.

The invention is particularly applicable to mechanisms in which a plurality of groups of contact elements are movable as a unit to put a particular group of said contact elements in contact with a corresponding group of fixed contact elements which are connected in electric circuits.

An important object of the invention is to provide a supporting member or shield upon which a soft fabric or other suitable material is carried in a way to overlie or engage said groups of movable contact elements so that when said groups of contact elements are moved to put a particular group of contact elements in contact with fixed contact elements, said fabric means automatically wipes or cleans said contact elements, thus keeping them clean at all times and eliminating the necessity for special service at regular intervals to clean said movable contact elements.

It is also an important object of this invention to provide a soft fabric or other material, with the means for holding it in engagement with the movable contact elements, of such a character that it will hold a lubricating or treating oil or solution, whereby to more effectively protect, clean and lubricate said contact points or elements so as to get the very best service therefrom.

Other objects and advantages of the invention will appear from the following detailed description of one practical embodiment thereof, taken with the accompanying sheet of drawings, in which:

Figure 1 is a vertical sectional view through a drum with the invention applied thereto; and

Figure 2 is a view showing a drum with its groups or rows of contact elements thereon, and showing one embodiment of the invention proper removed endwise therefrom.

Referring now in detail to the drawings, D designates a drum such as the contact supporting drum of a television tuning assembly having separate rows or groups of contact elements, as 3, 3, thereon and movable therewith as said drum is turned in selective tuning operation. Said drum also shows a holding ring 4 thereon, having indents or seats, as 4, therein to receive a spring held roller 5, clearly shown in Fig. l, for holding said drum in different selective positions for putting different groups or rows of contact elements in operating position, as will be understood, for this mechanism is old in TV sets and is shOWn only for the purpose of illustrating how the invention proper is applied thereto for protecting and cleaning the contact elements thereon.

There is also shown in Fig. 1 of the drawings a yieldingly supported contact element, as 6, of which there is a group or row to correspond with the rows or groups of contact elements on said drum. These yieldingly mount- "ice ed contact elements would have circuit connections thereto, as 6, in the usual manner. This also is old in the art.

The invention proper is shown removed from the drum D, at the left portion of Fig. 2, and is shown in place, in section, in Fig. 1. The invention as here embodied for explanatory purposes, consists of a supporting body or shield made of sheet yieldable metal, preferably of brass, and includes two laterally spaced extensions, as 7, 7, with a space 8 therebetwen, and through which the holding ring 4 projects, as seen in Fig. 1. At the opposite ends of said supporting body or shield it is extended, as at 9, with projecting end portions, as 9', to hook under the edge of the main frame or opening bounding edge of the tuning assembly housing, as at 9' in Fig. '1, for holding said shield in place. The opposite side of said holding body or shield is extended upwardly, as at 10, and has its edge slit to form a lip 10' to be hooked over the edge of the main frame, as seen in 10' in Fig. 1.

These fabric pieces 12, 12, which have their opposite ends wrapped around the ends of the two spaced extensions 7, 7, and the edges of the wing portions 11, 11, encircle the drum D about a major portion of the circumference thereof and overlie the contact elements 3, 3 thereon in such a way as to protect them and also to clean said contact points as said drum is turned to bring different groups or rows of contact points into engagement with the yieldingly supported contact points, as 6, which are positioned between the folded over ends of said fabric member, as seen in Fig. 1. As will be observed from the drawing, the body portion 9, the extensions 7, 7, and the wings 11, 11 are shaped so as to produce a cradle supporting the fabric strips 12, 12 at their ends closely adjacent the inwardly facing surfaces of the cradle to accommodate the tuning assembly drum D within the cradle in peripheral contact with the fabric strips 12, 12.

The cleaning unit of the present invention may be readily applied to the tuning units of existing television sets. by servicemen or owners. To apply the cleaning unit about the contact drum D of a conventional tuning unit, the yieldable extensions 7, 7 are sprung outwardly away from their associated wing portions 11, 11 to provide spacing between these elements to admit the contact drum D therethrough and permit the drum D to be seated within the cleaning unit with the contact elements 3 engaged about the major circumference of the drum D by the fabric wiping strips 12, 12. In practice, this is conveniently accomplished by springing the ends of the extension fingers 7, 7 and wing portions 11, 11 slightly apart relative to their normal spacing, and forcing the cleaning unit over. the contact drum D with the edges of the fabric encased fingers and wing portions in engagement with the drum periphery whereby the drum surface cams these edges apart a sufi'icient distance to allow the maximum diameter of the drum to pass therebetween. The cleaning unit thereupon snaps into position as the extension fingers 7, 7 return to their normal position and the cleaning unit is automatically centered properly relative to the drum D, with the fabric wiping strips 12, 12 engaging the contact elements 3.

While the lips 9' and 10' frictionally engage and hook over free edges of the tuning unit housing and assist in limiting the maximum extent to which the cleaning unit may be inserted into the tuning unit housing, the cleaning unit is maintained in assembled condition with the drum D solely through the extension of the fingers 7, 7 and body 9 about a major portion of the drum circumference.

Movement of the fabric wiping strips 12, 12 axially of the drum D which would shift them out of proper alignment with the contact elements 3 with which they are associated is prevented by providing a relieved space 8 between the fingers 7, 7 into which the drum holding ring 4 is fitted when the cleaning unit is assembled on the drum, disposing the adjacent edges of the fingers 7, 7 in position to abut the sides of the holding ring 4 upon axial shifting of the cleaning unit. Thus I have provided means for automatically cleaning the contact points or elements on a drum or other support therefor as they are moved to engage the contact elements connected with circuits in the usual manner. The fabric or cleaning member 12 is such that it can be moistened with oil or some suitable solution which will clean and also keep in good condition the contact elements and do away with the need for special cleaning to get better results.

While I have shown the invention applied to a television dr-um carrying contact elements, I do not limit it to this use or application, for it'can be applied to other forms of mechanism Where a group of contact elements are moved into and out of engagement with fixed contacts heads or elements, the fabric being related to the movable contact elements so that they will wipe on said fabric as they are moved to operating position.

I claim:

1. A contact element wiping unit for a drum tuning assembly of the type having a tuning assembly housing open along one side thereof and a drum rotatably supported Within said housing having contact elements in the periphery thereof; comprising a cradle of yieldable sheet material adapted to removably encompass a major portion of the circumference of the drum periphery and terminating in lip portions spaced apart a distance less than the length of the diameter of the drum whereby said cradle may be snapped in resiliently retained encompassing relation over said drum periphery, an elongated fabric wiping strip secured solely at its longitudinal ends to said lip portions to depend therefrom in close proximity to the inner surfaces of said cradle and form a seat for said drum in wiping relation thereto as the drum is rotated, and means for restraining said cradle against rotation about the axis of said drum during rotation of the drum.

2. A contact element Wiping unit for a drum tuning assembly of the type having a tuning assembly housing open along one side thereof and a drum rotatably supported within said housing having contact elements in the periphery thereof; comprising a cradle of yieldable sheet material adapted to removably encompass a major portion of the circumference of the drum periphery and terminating in lip portions spaced apart a distance less than the length of the diameter of the drum whereby said cradle may be snapped in resiliently retained encompassing relation over said drum periphery, an elongated fabric wiping strip secured solely at its longitudinal ends to said lip portions to depend therefrom in close proximity to the inner surfaces of said cradle and form a seat for said drum in Wiping relation thereto as the drum is 1'0- tated, and stop members on said cradle adapted to engage said housing and restrain said cradle against rotation during rotation of said drum.

3. A contact element wiping unit for a drum tuning assembly of the type having a tuning assembly housing open along one side thereof and a drum rotatably supported within said housing having contact elements in the periphery thereof; comprising a cradle of yieldable sheet material adapted to removably encompass a major portion of the circumference of the drum periphery and terminating in lip portions spaced apart a distance less than the length of the diameter of the drum whereby said cradle may be snapped in resiliently retained encompassing relation over said drum periphery, an elongated fabric wiping strip secured solely at its longitudinal ends to said lip portions to depend therefrom in close proximity to the inner surfaces of said cradle and form a seat for said drum in wiping relation thereto as the drum is rotated, stop members on said cradle adapted to engage said housing and restrain said cradle against rotation during rotation of said drum, and said cradle having aperture means therein adapted to receive means projecting from said housing when said cradle is assembled on said housing to restrain said cradle against movement axially of said drum.

4. A contact element wiping unit for a drum tuning assembly of the type having a tuning assembly housing open along one side thereof and a drum rotatably supported within said housing having contact elements in the periphery thereof; comprising a cradle of yieldable sheet material of sufiicient extent to overlie a major portion of the circumference of the drum periphery transversely of the axis of the drum including a base portion, integral wall portions projecting therefrom along generally divergent paths and integral lip portions projecting from the ends of said wall portions along generally converging paths, the maximum spacing between said wall portions being slightly greater than the diametric length of said drum and the spacing between said lip portions being less than said diametric length whereby said wall and lip portions may be snapped in encompassing relation with a major portion of the circumference of said drum and resiliently retained thereon by said converging lip portions, an elongated fabric Wiping tape secured terminally to said lip portions and extending freely therebetween along a path closely proximate to the inner surface of said base, wall, and lip portions to be supported in Wiping engagement with the contact elements on said drum periphery over a major portion of the drum circumference, and stop members on said cradle adapted to engage said housing and restrain said cradle against rotation during rotation of said drum.

References Cited in the file of this patent FOREIGN PATENTS 12,980 Great Britain June 3, 1912 

